Immediate serial recall of mixed-modality lists

Seven experiments are reported in which subjects were tested for immediate serial recall of mixed-modality lists. On mixed auditory-visual lists, there was an advantage for auditory items at all serial positions. This was due to both a facilitation of auditory items and an inhibition of visual items on mixed lists, as compared with single-modality lists. When presented on a list containing items read silently, recall of items that were silently mouthed by the subject demonstrated patterns similar to those found with auditory items. When presented on a list containing items read aloud, recall of mouthed items showed patterns similar to those found with silently read items. The auditory advantage on mixed lists was found even when the list items were acoustically similar or identical and was not reduced by midlist auditory suffixes. The results suggest that modality differences in recall of mixed-modality lists are based on information different from that responsible for modality differences in recall of single-modality lists.     

Transposition asymmetry in immediate serial recall

When participants confuse the position of items in immediate serial recall, they tend to recall transposed items too early rather than too late. This asymmetry of transposition errors was observed in four experiments. It increased as a function of list length, but was independent of report order, output position, cueing condition, and recall mode. The transposition asymmetry is consistent with error patterns in free recall and in regular speech production where transpositions are usually forward-looking. The asymmetry of transposition errors is discussed in terms of models of serial memory.     

Transposition asymmetry in immediate serial recall

When participants confuse the position of items in immediate serial recall, they tend to recall transposed items too early rather than too late. This asymmetry of transposition errors was observed in four experiments. It increased as a function of list length, but was independent of report order, output position, cueing condition, and recall mode. The transposition asymmetry is consistent with error patterns in free recall and in regular speech production where transpositions are usually forward‐looking. The asymmetry of transposition errors is discussed in terms of models of serial memory.     

The word-length effect in probed and serial recall

The word-length effect in immediate serial recall has been explained as the possible consequence of rehearsal processes or of output processes. In the first experiment adult subjects heard lists of five long or short words while engaging in articulatory suppression during presentation. Full serial recall or probed recall for a single item followed the list either immediately or after a 5-second delay to encourage rehearsal. The word-length effect was not influenced by recall delay, but was much smaller in probed than in serial recall. Examination of the serial position curves suggested that this might be due to a recency component operating in probed recall. Experiment 2 confirmed a word-length-insensitive recency effect in probed recall and showed that this was resistant to an auditory suffix, unlike the small recency effect found in serial recall. Experiment 3 used visual presentation without concurrent articulation. Under these conditions there was no recency effect for either recall method, but the word-length effect was again much smaller in probed than in serial recall. This was confirmed in Experiment 4, in which the presentation of serial and probed recall was randomized across trials, showing that the differences between recall methods could not be due to encoding strategies. We conclude that for visual presentation, at least part of the word-length effect originates in output processes. For auditory presentation the position is less clear, as serial and probed recall appear to draw on different resources. The nature of the output processes that may give rise to word-length effects is discussed.     

The unimportance of explicit spatial information in serial recall of visually presented lists

The superiority of auditory over visual presentation in short-term serial recall may be due to the fact that typically only temporal cues to order have been provided in the two modalities. Auditory information is usually ordered along a temporal continuum, whereas visual information is ordered spatially, as well. It is therefore possible that recall following visual presentation may benefit from spatial cues to order. Subjects were tested for serial recall of letter-sequences presented visually either with or without explicit spatial cues to order. No effect of any kind was found, a result which suggests (a) that spatial information is not utilized when it is redundant with temporal information and (b) that the auditory-visual difference would not be modified by the presence of explicit spatial cues to order.     

Associative factors in free recall

An experiment on the free recall of 18-word lists is reported in which variations were made in associative frequency, word frequency and the number, and therefore size, of the presented groups. Recall efficiency was positively related to increasing associative frequency and larger presented group size. Measures of clustering were obtained along with subjects' own reports on the associative labels helpful to them in organizing their recall. A two-level storage model is proposed to account for the results.     

Beyond the articulatory loop: A semantic contribution to serial order recall of subspan lists

In two experiments, serial order recall of short lists of content and function words under quiet and articulatory suppression conditions was examined in order to assess the hypotheses that (1) semantic attributes of words contribute to short-term-memory performance, and (2) do soindependently of effects attributable to the articulatory loop component. In Experiment 1, content words were better recalled than function words; both word types were equally impaired by suppression. This provides support for the notion that semantic coding makes an independent contribution to span performance. This word-class effect disappeared in Experiment 2, when content and function words were matched for imageability. These data suggest that at least some aspects of meaning contribute to serial order recall performance for short lists, independently of the articulatory loop.     

Cue-dependent effects in recall of categorized lists

Noncued and cued recall of categorized lists are similar in a number of ways: They show the same rate of gain in item recall with increasing category size; they both produce serial position effects within categories; and they both show a “some-or-none” pattern of with-category recall frequency. Cued and noncued recall differ in other respects: There is a great improvement in item and in category recall attendant on the provision of cues, and only noncued recall displays a list position effect. The points of similarity are taken to indicate that both cued and noncued recall measure the same underlying processes. The points of differences suggest the utility of cueing procedures in identifying the origin of characteristics of recall, according to the principle that any feature of noncued recall that is altered by provision of cues must originate in the retrieval process; features resistant to such modification represent encoding or storage effects.     

Strategies in the recall of clusterable lists

The present study assessed the effectiveness of a multi-session training aproach intended to teach mildly retarded adolescents to discover and utilize categorical list structure. The performance of a group of trained retarded individuals was compared with that of another group of retarded individuals who had simply received practice with the training materials. The performance of both retarded groups was evaluated relative to that of a group of equivalent-CA normal adolescents. Recall transfer with a new word list was indicated by the finding that trained retarded subjects achieved a criterion of perfect recall in fewer trials than untrained retarded subjects. Differences in the use of categorization strategies by normal and retarded subjects were interpreted in the light of the automatic-controlled processing distinction of Schneider and Shiffrin (1977).     

Associative retrieval processes in free recall

I present a new method for analyzing associative processes in free recall. While previous research has emphasized the prominence of semantic organization, the present method illustrates the importance of association by contiguity. This is done by examining conditional response probabilities in the output sequence. For a given item recalled, I examine the probability and latency that it follows an item from a nearby or distant input position. These conditional probabilities and latencies, plotted as a function of the lag between studied items, reveal several regularities about output order in free recall. First, subjects tend to recall items more often and more rapidly from adjacent input positions than from remote input positions. Second, subjects are about twice as likely to recall adjacent pairs in the forward than in the backward direction and are significantly faster in doing so. These effects are observed at all positions in the output sequence. The asymmetry effect is theoretically significant because, in cued recall, nearly symmetric retrieval is found at all serial positions (Kahana, 1995; Murdock, 1962). An attempt is made to fit the search of associative memory model (Raaijmakers & Shiffrin, 1980, 1981) with and without symmetric interitem associations to these data. Other models of free recall are also discussed.     

Short-term serial tactual recall: effects of grouping on tactually probed recall of Braille letters and nonsense shapes by blind children

The study tested the hypothesis that grouping has adverse effects on the recall of tactual shapes but facilitates the recall of tactual letters on the assumption that this depends on different processes. A further question was the relation of grouping to letter recall span (set-size). Tactually probed recall of tactually presented serial nonsense and letter shapes by blind children was tested under grouped and ungrouped conditions. Results showed a highly significant interaction between list type and grouping, and a (smaller) higher order interaction between set size list type and grouping, in the predicted directions. Grouping had adverse effects on nonsense shape recall. Letter recall was better and was facilitated by grouping, except by subjects with poor letter recall spans who were also slow at letter naming. Mental and chronological age were associated with higher scores, but unlike set size, did not relate differentially to letter grouping. It was argued that the form of coding is a factor in determining the nature of processing and in recall efficiency.     

Executive processing in free recall of categorized lists

The present study examines the cognitive processes that operate in free recall of categorized lists by manipulating semantic structure of the lists and using a dual task methodology to restrict the processes that make demands on limited-capacity resources, the central executive resources. Relying on the assumption that, in free recall of categorized lists, the search for category names is a strategic controlled process that demands executive resources, lists with different numbers of categories ranging from 2 to 6 were employed. The results showed an effect of a secondary task on retrieval in the 4- and the 6-category list conditions, but not in the 2-category list condition. In contrast to retrieval, the secondary task interference at encoding produced an effect on recall of all three types of lists. An interesting finding was that an effect on clustering was found only when interference was present at encoding, not when it was at retrieval. This finding was in line with the suggestion (Troyer, Moscovitch, Winocur, Alexander, & Stuss, 1998) that switching (shifting between different category items) rather than clustering is related to executive functioning, and suggested that clustering may be a measure of two different types of processing: (1) executive processing at encoding and (2) automatic processing at retrieval. In addition, a different pattern of results was obtained when low frequency category words were used, indicating that the frequency of category words is an important determinant in free recall of categorized lists. Overall, the present results support the two-process account of retrieval of category words (Rosen & Engle, 1997) and the view that there are fundamental differences between encoding and retrieval processes (Naveh-Benjamin, Craik, Guez, & Dori, 1998; Naveh-Benjamin & Guez, 2000).     

Rehearsal in immediate serial recall

We report for the first time overt rehearsal data in immediate serial recall (ISR) undertaken at three presentation rates (1, 2.5, and 5 sec/word). Two groups of participants saw lists of six words for ISR and were required either to engage in overt rehearsal or to remain silent after reading aloud the word list during its presentation. Typical ISR serial position effects were obtained for both groups, and recall increased with slower rates. When participants rehearsed, they tended to do so in a cumulative forward order up to Serial Position 4, after which the amount of rehearsal decreased substantially. There were similarities between rehearsal and recall data: Both broke down toward the end of longer sequences, and there were strong positive correlations between the maximum sequence of participants' rehearsals and their ISR performance. We interpret these data as suggesting that similar mechanisms underpin both rehearsal and recall in ISR.     

Adding sound to lipread lists: The effects on serial recall of adding an auditory pulse train and a pure tone to silently lipread lists

These investigations examined subjects’ serial recall of lipread digit lists accompanied by an auditory pulse train. The pulse train indicated the pitch of voiced speech (buzz-speech) of the seen speaker as she was speaking. As a purely auditory signal, it could not support item identification. Such buzz-speech recall was compared with silent lipread list recall and with the recall of buzz-speech lists to which a pure tone had been added (buzz-and-beep lists). No significant difference in overall accuracy of recall emerged for the three types of lipread list; however, there were significant differences in the shape of the serial recall function for the three list types. Recency characterized the silent and the buzz-speech lists, and these lists differed in their varying susceptibilities to a range of speechlike suffixes. By contrast, adding a pure tone to a buzz-speech list (buzz-and-beep) produced little recency and no further recall loss as a function of suffix type. We discuss these effects with reference to the contrast betweensensory-similarity and speechlikeness accounts of auditory recency and suffix effects. Sensory similarity accounts cannot capture the effects reported here, but processing in a speech mode (buzz-and-beep) need not always lead to recency effects like those resulting from clearly heard or lipread lists.     

Word frequency effects in immediate serial recall of pure and mixed lists: tests of the associative link hypothesis.

In immediate serial recall, high-frequency words are better recalled than low-frequency words. Recently, it has been suggested that high-frequency words are better recalled because of their better long-term associative links, and not because of the intrinsic properties of their long-term representations. In the experiment reported here, recall performance was compared for pure lists of high- and low-frequency words, and for mixed lists composed of either one low- and five high-frequency words or the reverse. The usual advantage of high-frequency words was found with pure lists and this advantage was reduced, but still significant with mixed lists composed of five low-frequency words. However, the low-frequency word included in a high-frequency list was recalled just as well as high-frequency words. Results are challenging for the associative link hypothesis and are best interpreted within an item-based reconstruction hypothesis, along with a distinctiveness account.     

Proactive interference in immediate serial recall

Two experiments yielded significant inter-list proactive interference (PI) in immediate serial recall of nine-consonants lists. This argues against the assumption that intra-trial rehearsal is sufficiently powerful to prevent PI from occurring. In the first experiment PI proved to be more pronounced in the case of visually than of auditorily presented lists to the extent that the modality effect on the prerecent items could be completely attributed to PI. PI also enlarged the effect of output interference through reversed order recall. These findings were confirmed in the second experiment which also showed that the effect of PI persisted at a slower presentation rate, suggesting that the role of rehearsal in counteracting PI should not be overestimated. Implications of these results for current notions on short-term retention are discussed.     

Output order in immediate serial recall

In two experiments, we examined the effect of output order in immediate serial recall (ISR). In Experiment 1, three groups of participants saw lists of eight words and wrote down the words in the rows corresponding to their serial positions in an eight-row response grid. One group was precued to respond in forward order, a second group was precued to respond in any order, and a third group was postcued for response order. There were significant effects of output order, but not of cue type. Relative to the forward output order, the free output order led to enhanced recency and diminished primacy, with superior performance for words output early in recall. These results were replicated in Experiment 2 using six-item lists, which further suggests that output order plays an important role in the primacy effect in ISR and that the recency items are most highly accessible at recall.